Wanted to touch on Switch.
So, in a supply constrained environment, comparing point in time sales to benchmarks doesn't do a whole lot of good for forecasting the future. Comparing Switch and Wii is interesting to look at a point in time, but because both were supply constrained, launched at different times of the year, etc it's not useful for the outlook.
All a LTD comparison from Switch to Wii will tell you is something about the supply chain and maybe something about regional allocation.
What to do, then?
Well, you gotta get a little creative.
Nintendo is on the record saying they want to get to 10m shipped WW in the first calendar year (2017).
From there, you can do some regional allocation guesses. I'm assuming somewhere in the neighborhood of 40-44% of that will go to the US.
If Nintendo does ship 10m WW, and the US gets that percentage of allocation, then you can estimate that US will get 4-4.4m or so.
So that gets you to your sales cap for the year. Then, you have to estimate what % of that you think will sell.
Finally, you can take that number, and compare to the first 10 months of other platforms to get to a better comparable.
Now the thing to watch is Nintendo's earnings and to see if they have an updated planned ship number for the year, and then you can start the exercise over.
Sorry for the long post. It's difficult to use normalized demand sales analytics (like benchmark comps) when demand isn't normalized for the product being analyzed or the benchmarks.
Media Create and Famitsu always show enormous, like 85%-ish weekly drops for RPGs but for some reason I wasn't sure if North American RPG sales behaved the same super front-loaded way.
I can't really get into specific title performance, but yes, popular JRPGs tend to have similar drops (on a monthly basis) from month 1 to month 2. The JRPG fanbase is passionate, and must have the latest and greatest day 1.